The prior discloses a number of ski boots of the aforementioned type. However, in general the inner slipper is merely placed in the corresponding shell, without being truly held in place. Some manufacturers have tried to introduce improvements in these boots by designing a device for connecting the inner slipper; this is the case, for example, in the boot corresponding to European Patent Application No. EP 0351 396, which discloses an inner slipper connected to the rear cover of the upper by means of a position-retention strap arranged in the lower part of the rear tongue of the slipper. However, this type of connection is not satisfactory. In fact, when the rear cover pivots, the slipper opens only very slightly, thus making it troublesome to put on the boot; furthermore, the rear space between the tongue and the rear cover can fill with snow. Nothing restricts the rearward pivoting of the rear cover, and, when the boot is put on, insertion of the foot may cause the rear tongue belonging to the slipper to descend into the boot, a phenomenon which, of course, makes it even more difficult, and even impossible, to put on the boot.